Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Purpose: Computer assisted planimetry is a possible method for two dimensional measurement of the structures of the optic nerve head. Our purpose was to test the intraobserver - interphotographic and interobserver reproducibility of this method.
Patients and methods: During the course of our first examination we took slides of the optic nerve heads from 10 eyes of 10 patients (n = 7 primary open angle glaucoma (POAG), n = 3 ocular hypertension (OHT)) using a telecentric Zeiss fundus camera. From each papilla 3 photos were taken, which were evaluated by the same examiner on different days using two - dimensional computer assisted planimetry (3x10 slides for one observer). During the course of our second examination we took slides of the optic nerve heads of 27 eyes of 27 patients (n = 19 POAG, 8 OHT). 3 different examiners on separate days performed planimetric measurements from the same slide (27 slides x 3 observers). During both examinations the following structures were measured: surface of the optic disc, and its maximal and minimal horizontal diameter, surface and maximal and minimal horizontal diameter of the of the optic cup, the surface of the neuroretinal rim area in four different sectors, and the surface of the parapapillary zones alpha and beta.
Results: During the course of our first examination we found that except of the parapapillary regions the variability was less than 10 %. The measurements of the parapapillary regions showed large variances ( alpha zone: 46.5% SD +- 40.3 ; beta zone: 22.5 SD +- 30.4). During the course of the interobserver examinations the tendencies were the same. Except of the parapapillary regions the variances of the measurements did not exceeded 12%.
Conclusions: In both examinations the best reproducible structures were the surface and the diameters of the optic disc. The parameters of the optic cup and the neuroretinal rim had larger variances but did not exceeded 12%. The interobserver measurements showed larger variances than the intraobserver - interphotographical ones. The measurements of the parapapillary regions are less reproducible.

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Presentation Number SApapp0586
Keywords: planimetry, glaucoma, optic nerve head, interobserver, intraobserver